CA2262049A1 - Thermally sensitive valve - Google Patents

Abstract

A thermally sensitive valve for initiating actuation of apparatus in response to an increase to a predetermined level of ambient temperature has a tubular body adapted to be fitted to a conduit containing pressurized fluid and having an inlet through which such fluid may enter a passageway in the body. The valve body also has a fluid outlet and a piston which normally occupies a position which prevents the exhaust of fluid from the passageway. The piston is biased by the pressure of the fluid to a position which enables the exhaust of fluid from the passageway, but movement of the piston to such position is restrained by a linkage having a pair of links bonded together by a eutectic material which melts in response to a rise in ambient temperature to a predetermined level, thereby enabling the links to separate and remove the restraint on the piston. The linkage is exposed on all sides to ambient temperature.

Description

THERMALLY SENSITIVE VALVE
This invention relates to a thermally sensitive valve of the kind especially adapted for use in a pressure fluid system having a control device which is to be actuated in response to a predetermined rise in ambient temperature.
There are many instances in which a rise in ambient temperature requires the actuation of a 10 control device such as a signal, a fire door, a damper, and the like. Some of such devices are associated with a pressurized fluid system which applies or maintains a force on the device that is to be controlled and which is maintained in a 15 predetermined position by the pressure of the fluid.
A reduction in the fluid pressure enables the control device to be actuated.
In many instances actuating mechanisms proposed heretofore have been relatively slow to 20 react in response to rising temperature. They also have been composed of multiple and complex parts that require considerable skill and time to assemble, and which are difficult to remove for testing or replacement.
Apparatus constructed in accordance with the invention overcomes the aforementioned difficulties by the provision of a tubular valve body having an internal passageway adapted for communication at one end with the pressure fluid and 5 having an outlet or vent between its ends for venting the pressure fluid in response to a predetermined rise in ambient temperature.
The valve construction includes a piston normally occupying a position which disables the 10 flow of pressure fluid through the valve body to the vent, and such valve is maintained in that position by means of a latch and a fusible linkage having two parts which normally are maintained in fixed relation, but which separate when the temperature 15 rises to a predetermined level. Thereafter the pressure of the fluid displaces the piston to a position in which pressurized fluid is enabled to escape through the vent, thereby enabling a reduction in the pressure of the pressurized system 20 and actuation of the control device.
Apparatus constructed in accordance with preferred embodiments of the invention is disclosed in the accompanying drawings wherein:
25 Figure 1 is an elevational view of a first embodiment;

Figure 2 is a vertical sectional view taken on the line 2-2 of Figure 1;
Figure 3 is a sectional view similar to Figure 2, but of a second embodiment; and 5 Figure 4 is a sectional view similar to Figure 2, but of a third embodiment.
A valve assembly formed in accordance with the embodiment shown in Figures 1 and 2 is 10 designated generally by the reference character 1 and comprises a metallic, tubular body 2 having a shank 3 at one end provided with two different diameter threaded portions 4 and 5, thereby enabling the valve to be mounted on supports having threaded 15 openings of different diameters or to enable the body to accommodate a lock nut. The body 2 has a bore 6 which communicates internally with a counterbore 7 of larger diameter, the bore and counterbore forming a passageway through the body.
20 The bore 6 is open at both ends to form an inlet 8 and an outlet 9, respectively, and the body 2 also has at least one vent opening 10 which establishes communication between the counterbore 7 and the exterior of the valve. The vent 10 also constitutes 25 an outlet for the passageway.
Slideably accommodated in the counterbore 7 is a piston 12 having a reduced diameter shank that is encircled by a spring 13, one end of which seats on a shoulder 14 between the bore 6 and the counterbore 7 and the opposite end of which seats on a flange 15 of the piston. The flange has an annular groove 16 in which is accommodated an O-ring seal 17 which bears against the surface of the counterbore 7. The piston 12 has an axial projection 18 extending from the flange 15.
A latch 20 has a shank 21 which extends through a slot 22 in the wall of the body 2 and through an opening 23 in the body wall opposite the slot 22. One end of the shank 21 is free whereas the opposite end is formed as a hook 24 which passes through the opening 23 and forms a pivotal connection of the latch to the valve body 2.
A fusible retaining linkage 25 of the kind disclosed in U.S. Patent No. 5,120,152 (the disclosure of which is incorporated herein by reference) has a first link 26 and a second link 27 which are separate from one another, but which are maintained assembled by a fusible, eutectic material in the manner disclosed in the above identified patent. The link 26 has at one end an opening 28 through which the shank 21 of the latch 20 extends.
Preferably, the shank has a slightly deformed section 29 to facilitate assembly of the latch and the retaining linkage 25. The link 27 has at one end an opening 30 through which extends a headed anchor screw 31, such screw extending into a 5 threaded opening formed in the body 2. A washer 32 formed of thermally insulating material has an opening through which the screw 31 extends to provide thermal insulation between the link 27 and the body 2 and minimize the transfer of heat from the link to the valve body.
In the arrangement of the parts as shown in Figures 1 and 2, the valve assembly 1 is adapted to be threaded into an opening formed in a pipe or other conduit 33 in which air or other fluid is 15 maintained under pressure. The piston 12 initially or normally occupies a first position in which the seal 17 disables fluid from passing through the passageway to the outlet 9 or the vent 10. The piston is maintained in such position by the latch 20 20, the shank 21 of which seats on and precludes movement of the piston in the direction of the outlet 9 notwithstanding the forces acting on the piston due to the pressure of the fluid and the spring 13.
25 The eutectic material by means of which the links 26 and 27 are bonded together has a predetermined temperature at which the material melts. When the ambient temperature rises to the melting temperature of the eutectic material, the two links 26 and 27 will separate, thereby enabling pressurized fluid in the conduit 33 to displace the piston 12 in a direction to release the latch 20.
The piston can move to a position in which the outlet vent 10 is in communication with the fluid in the conduit 33, thereby decreasing the pressure within the conduit 33.
The conduit 33 forms part of a system which is connected to one or more control devices such as a damper, a fire door, a visual or audible signal, or the like and which are normally maintained in a selected condition by the pressure of fluid in the conduit. When such pressure is relieved, following displacement of the piston 12, the control device will be moved to another position to actuate the signal, damper, or the like.
The fusible retaining linkage 25 is wholly external of the valve body 2 and, therefore, is wholly exposed on all sides to ambient temperature.
Further, the insulating washer 32 will prevent significant heat transfer between the linkage 25 and 25 the body 2 which, in many cases, is cooled by the fluid. Consequently, the valve mechanism 1 has an extremely rapid reaction time to a rise in ambient temperature to the level of the predetermined temperature of the eutectic material.
All of the parts of the valve mechanism are easily accessible from outside the valve.
Consequently, it is simple to test the valve or replace any of its operating parts.
The apparatus shown in Figure 3 corresponds in many respects to that previously 10 disclosed, so corresponding reference characters refer to corresponding parts. The embodiment of Figure 3 differs from that of Figures 1 and 2 in that the Figure 3 embodiment does not include a spring like the spring 13, but it does include a cap 34 threaded onto the outlet end of the body 2. The cap 34 has an opening 35 through which an extension 36 of the piston 12 projects. The embodiment of Figure 3 includes a latch 20a comprising an arm 21a having an opening therein for the accommodation of 20 one end of the extension 36 and a right angular arm 37 which is coupled to the link 26 by means of a rivet 38. The arm 21a is maintained assembled with the piston extension 36 by a nut 39.
The operation of the embodiment shown in 25 Figure 3 corresponds to that of the earlier described embodiment.

The embodiment shown in Figure 4 is more simplified than either of the other two embodiments described above. In the Figure 4 embodiment a tubular, metallic body 41 has a uniform diameter 5 passageway 42 extending therethrough in which slideably is accommodated a piston 43 having an external annular groove in which is received an O-ring seal 44. The body 41 includes a pair of vent openings 45 which normally are at a level above that of the piston 43, and the body 41 also is provided with a pair of openings through which an anchor pin 46 extends. The pin has a diameter much less than that of the passageway 42 and preferably has a press fit in its openings, or is otherwise sealed so as to avoid the escape of pressurized fluid from the body 41.
A latch 47 comprises a rod 48 one end of which is threaded into or otherwise fixed to the piston 43, and the other end of which is bent to form a section 49 which extends through a slot 50 in the wall of the body 41 and also through the opening 28 of the link 26 of the linkage 25. The other link 27 of the linkage accommodates in its opening 30 a hooked end 51 of the anchor pin 46.
The apparatus shown in Figure 4 has an inlet 52 at one end of the body 41 and an outlet 53 _ g _ at the opposite end. That part of the body 41 adjacent the inlet 52 may be threaded or otherwise constructed for sealed accommodation in a conduit like the conduit 33 in which pressurized fluid is maintained. In this embodiment the anchor pin 46 does not prevent fluid pressure from acting on the piston 43 in a direction to move it toward the outlet end 53, but the reaction between the latch 47 and the linkage 25 prevents movement of the piston 43 to a position in which the vent openings 45 are in communication with the inlet 52 until such time as the links of the linkage 25 separate.
The disclosed embodiments are representative of a presently preferred form of the invention, but are intended to be illustrative rather than definitive thereof. The invention is defined in the claims.
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Claims (16)

1. A valve construction operable in response to a change in ambient temperature, said construction comprising a body having one end adapted for accommodation in a pressurized fluid conduit, said body having a fluid passageway therein, said passageway having an inlet adjacent said one end of said body through which fluid may enter said passageway when said one end of said body is accommodated in said conduit, and an outlet spaced from said inlet; a piston accommodated in said passageway for movement from a first position in which said piston disables flow of fluid through said passageway from said inlet toward said outlet to a second position in which fluid is enabled to flow from said inlet through said passageway to said outlet; latch means operable in latched condition to exert a restraining force on and maintain said piston in said first position; and separable thermally sensitive retaining means coupled to and acting on said latch means for releasably maintaining said latch means in said latched condition, said retaining means having separable links normally joined together but being responsive to a predetermined rise in ambient temperature to separate and disable said latch means, thereby enabling the pressure of fluid in said conduit to move said piston from said first position to said second position.

2. The construction according to claim 1 wherein said retaining means is wholly external of said body.

3. The construction according to claim 1 including yieldable means acting on said piston and yieldably urging said piston towards said second position.

4. The construction according to claim 1 including a seal reacting between said piston and said body and being operable to prevent the flow of fluid through said passageway past said piston.

5. The construction according to claim 4 wherein said piston comprises a plug having an enlargement between its ends, said seal being carried by said enlargement.

6. The construction according to claim 4 wherein said seal is carried by said piston.

7. The construction according to claim 1 wherein the links of said retaining means are secured to one another by a eutectic substance which melts in response to said predetermined rise in ambient temperature.

8. The construction according to claim 1 including a fixed anchor at one end of one of said links securing said one of said links to said body, and wherein said latch means comprises an arm pivoted to one end to said body and engaging said piston, said arm having its other end connected to the other of said links.

9. A valve for use in a pressure fluid system comprising a body adapted at one end for accommodation in a conduit containing a pressurized fluid, said body having a passageway therein adjacent one end of which is an inlet for communication with fluid in said conduit, said passageway having an outlet spaced from said inlet for exhausting fluid from said passageway; a piston slideably accommodated in said passageway for movement from a normal first position in which said piston disables the flow of fluid through said passageway from said inlet to said outlet, to a second position enabling the flow of fluid through said passageway from said inlet to said outlet;
latch means acting on said piston and having a normal position maintaining said piston in said first position; and thermally sensitive retaining means acting on said latch means for releasably maintaining said latch means in said first position, said retaining means comprising a linkage having links normally joined to one another, said linkage having opposite ends one of which is coupled to said latch means and the other of which is coupled to said body, said links being separable from one another in response to a rise in ambient temperature to a predetermined level thereby to release said latch means and enable said piston to move to said second position.

10. The valve according to claim 9 including spring means acting on said piston and yieldably urging the latter to said second position.

11. The valve according to claim 9 wherein said body is tubular and wherein said latch means comprises an arm extending transversely of said body across said passage and being pivotally coupled at one end to said body at one side of said passageway, and at its opposite end to said retaining means.

12. The valve according to claim 11 wherein said piston seats on said arm when said piston is in said first position.

13. The valve according to claim 12 wherein said piston is movable from said first position toward said second position in response to the release of said latch means by said retaining means.

14. The valve according to claim 9 including anchor means connecting said retaining means to said body.

15. The valve according to claim 9 including thermal insulating means interposed between said retaining means and said body at the coupling of said other end of said other of said links to said body.

16. The valve according to claim 9 wherein said retaining means is wholly external of said body.